Bursting strength ISO 13938-1 (Part-I)

TEXTILE: QUALITY AND
PERFORMANCE STANDARDS

Textiles—Bursting properties of fabrics.
Part-1
Hydraulic method for determination of
bursting strength and bursting distension.
ISO 13938-1:2015

Scope
 This standard describes a hydraulic method for the determination of
bursting strength and bursting distension of textile fabric. In this part a
hydraulic pressure is applied using a constant rate of pumping device.
The method is applicable to knitted, woven, nonwoven and laminated
fabrics. It may be suitable for fabrics produced by other techniques. The
test is suitable for test specimens in the conditioned or wet state. From
the available data there appears to be no significant difference in the
bursting strength results achieved using hydraulic or pneumatic burst
testers, for pressures up to 800 kPa. This pressure range covers the
majority of performance levels expected of general apparel. For specialty
textiles requiring high bursting pressures, the hydraulic apparatus is
more suitable.

Principle
 A test specimen is clamped over an expansive diaphragm by means of a
circular clamping ring. Increasing fluid pressure is applied to the
underside of the diaphragm, causing distension of the diaphragm and the
fabric. The volume of fluid is increased at a constant rate per unit time
until the test specimen bursts. The bursting strength and bursting
distension are determined.

Apparatus and Materials
Bursting tester
Metrological confirmation of the bursting tester shall be carried out in accordance
with EN 30012-1:1993.The bursting tester shall comply with the following
requirements:
The apparatus shall be capable of producing various constant rates of increase in
volume per unit time between 100 cm3/min and 500 cm3/min to within ±10 % of the
indicated value. If the apparatus is not equipped to adjust fluid volume, a testing
time to burst of (20 ±5) s may be applied. This shall be indicated in the test report.

Bursting pressure shall be indicated with an accuracy of ±2 % of full scale
range above the first 20 % of range. Height at burst up to 70 mm shall be
indicated with an accuracy of ±1 mm. Zero position of the measuring gauge
shall be adjustable to accommodate the thickness of the test specimen.
Means for indicating the volume at burst (if available) to within ±2 % of the
indicated value.
A test area of 50 cm2 (79,8 mm diameter) shall be used. Other test areas of
100 cm2 (112,8 mm diameter) or 10 cm2 (35,7 mm diameter) or 7,3 cm2
(30,5 mm diameter) may be used, if the preferred test area is not applicable in
the existing testing equipment, or due to high or low expansion of the fabric or
other fabric requirements, or by mutual agreement

The clamping device shall provide for clamping of the test specimen securely
without distortion or damage and prevent slippage during the test. The clamping
ring shall allow undisturbed vaulting of highly expansive fabrics (e.g. fabric test
specimens whose height at burst is greater than half of the test specimen
diameter). All test specimen clamping ring inner diameters shall be accurate to
±0,2 mm. To avoid test specimen damage a small curvature at the inner edge of
the clamping ring facing the test specimen is recommended.
A safety cover shall enclose the clamping device during the test when the
expansion of the test specimen takes place. It shall allow clear observation of the
expansion of the test specimen during the test.
The diaphragm shall meet the following requirements:
- thickness up to 2 mm;
- highly expansive;
- if the diaphragm is to be used several times, it shall be elastic within the range
of height at burst observed during the test resistant against pressurizing fluids
used.

The diaphragm shall meet the following requirements:
- thickness up to 2 mm;
- highly expansive;
- if the diaphragm is to be used several times, it shall be elastic within the range
of height at burst observed during the test resistant against pressurizing fluids
used.

Atmospheres for conditioning
and testing
The atmospheres for preconditioning, conditioning and testing shall be as
specified in ISO 139:1973.
Preconditioning and conditioning are not required for wet tests.

Either select samples in accordance with the procedure laid down in the
material specification for the fabric, or as agreed between the interested parties.
In the absence of an appropriate material specification, an example of a suitable
sampling procedure is given in annex A. Avoid areas that are folded or creased,
selvedges and areas not representative of the fabric. The system of clamping
used generally permits tests to be applied without cutting out test specimens
Sampling

Prior to testing the sample shall be conditioned in the relaxed state in
accordance with as per ISO 139. During conditioning and testing maintain
the test specimens in the atmosphere for conditioning and testing in
accordance with ISO 139.
Set a test area of 50 cm2 or as buyer agreement -
Not-1: For most fabrics, particularly knitted fabrics, the test area of 50 cm2 is
applicable. For fabrics with low extensibility (known from previous experience
or preliminary testing), e.g. for fabrics for technical application, a test area of
100 cm2 is recommended. In cases where these conditions cannot be met or
are not appropriate alternative test areas in accordance may be used if
mutually agreed.
Note-2: Comparison of result requires the test to be perform with the same
test areas and rates of increase in volume
Procedure

Set a constant rate of increase in volume of between 100 cm3/min and 500
cm3/min depending on test area and fabric requirements. Or adjust a time to distend
a test specimen to burst of (20 ±5) s using preliminary trials, if a constant rate of
increase in volume is not applicable.
Place the test specimen over the diaphragm so that it lies in a flat tensionless
condition, avoiding distortion in its own plane. Clamp it securely in the circular holder,
avoiding jaw damage, to prevent slippage during the test. Place the distension
recording device into the measuring position and adjust it to the zero position. Fasten
the safety cover in position according to machine requirements. Apply pressure to the
test specimen until the fabric bursts.
Immediately after burst, reverse the apparatus to starting position. Note bursting
pressure and height at burst and/or bursting volume. If the test specimen bursts close
to the edge of the clamping device, report this fact. Reject jaw breaks occurring within
2 mm of the clamping line. Repeat the test at least four more times at different places
on the fabric. The number of test specimens may be increased if agreed mutually.
Procedure

With the same test area and rate of increase in volume or time to burst as
that employed in the above tests, distend the diaphragm without the presence
of a test specimen by an amount equal to the mean height at burst or the mean
volume at burst of the test specimen. Note the pressure at this distension of the
diaphragm as the "diaphragm pressure".
Diaphragm Correction

For tests in the wet condition, immerse the test specimen for a period of 1 h
in grade 3 water in accordance with EN ISO 3696:1995 at a temperature of (20
±2) C. For tropical regions, temperature according to ISO 139:1973 may be
used. An aqueous solution containing not more than 1 g of a nonionic wetting
agent per litre may be used instead of water. Immediately after removal of a
test specimen from the liquid and briefly placing it on blotting paper to remove
excess water and perform the test accordingly.
Diaphragm Correction

Calculation and expression of results
Calculate the arithmetic mean of the bursting pressure values in kilopascals. From
this subtract the diaphragm pressure in kilopascals as determined according to obtain
the bursting strength. Round the result to three significant figures.
Calculate the arithmetic mean of the height at burst values in millimetres. Round the
result to two significant figures.
If required, calculate the arithmetic mean of the volume at burst values in cubic
centimeters. Round the result to three significant figures.
If required, calculate the coefficient of variation and the 95 % confidence limits for
the bursting pressure and height at burst and, if required, volume at burst. Round the
coefficient of variation to the nearest 0,1 % and the 95 % confidence limits in
accordance with the mean values.

The test report shall include the following information
a) The number and year of publication of this part of this standard and date of test;
b) Identification of test sample and sampling procedure, if required;
c) Make and model of bursting tester used;
d) test area used, in square centimeters;
e) Rate of increase in volume or time to burst;
f) Number of test specimens tested and number of bursts close to clamping device
and number of tests rejected;
g) Observation of bursting behavior (e.g. rupture of one or both thread directions);
h) State of test (conditioned or wet);
i) Any deviation from the given procedure.
Test Report

 The test result shall include the following information
a) Mean bursting strength, in kilopascals;
b) mean height at burst, in millimeters;
c) mean volume at burst, in cubic centimeters, if required;
d) the coefficient of variation of the relevant values, in percent, if required;
e) the 95% confidence limits, in units of the relevant mean values, if required.
Test Results

Bursting strength ISO 13938-1 (Part-I)

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Bursting strength ISO 13938-1 (Part-I)